How to Replace a Bosch Washing Machine Drain Pump (BSH 00145787)

The drain pump evacuates water from the tub. When it fails: E18 error (drain timeout), water remains after cycles, or grinding/clicking from bottom-left. BSH 00145787 fits most models.

Before You Start

• Tools needed: Torx T20 (if removing panels), flathead screwdriver, pliers, shallow pan, towels
• Parts needed: BSH 00145787 ($65-$85)
• Time required: 25-40 minutes
• Difficulty: Intermediate
• Safety warning: Disconnect power and water. Drain all water from filter area first. The pump area retains water.

Step-by-Step Instructions

Step 1: Drain Residual Water

Open the service flap (bottom-left). Use the small drain hose to drain water into a container. Then slowly unscrew the filter cap counterclockwise to release remaining water (200-500ml expected). Remove the cap and clean out debris.

Step 2: Access the Pump

From below (recommended): Lay the machine on its back carefully. The pump is visible from the base without panel removal.

From the front: Remove the bottom kick plate. On some models, the pump connections are accessible without further disassembly.

Step 3: Disconnect the Old Pump

Unplug the 2-pin electrical connector from the pump motor (press tab, pull). Release both hose connections: squeeze spring clamps with pliers, slide back, pull hoses off. Have towels ready for residual water.

The pump uses a bayonet mount on most Bosch models: twist the pump housing counterclockwise ~30 degrees until it releases, pull out. Some models use 2-3 Torx T20 screws instead.

Step 4: Install the New Pump

Transfer the filter cap if not included with new pump. Position in bayonet mount, twist clockwise until locked (or screw in). Reconnect both hoses (push on firmly), slide spring clamps back to proper position. Reconnect electrical connector.

Step 5: Test

Stand machine upright. Restore water and power. Run a Rinse + Spin cycle. Listen during drain phase: should hear steady hum (not grinding or clicking). Verify E18 clears. Check all connections for leaks during drain.

Troubleshooting

• E18 persists: Hose clamp not engaged (air leak reduces suction). Also check drain hose height (max 39 inches above floor).
• Pump runs but no water drains: Blockage in drain hose (not pump). Disconnect and inspect.
• New pump clicks: Shipping protector may still be installed, or debris fell in during install. Remove and inspect.
• Slow drain: New pump is correct model but filter cap O-ring is worn (from old cap transfer). Check seal.

When to Call a Professional

• E18 persists after pump replacement and drain hose is verified clear (control board issue)
• Water damage from prolonged E18 before diagnosis (assess safety of electrical components)
• Pump housing in the tub is cracked where the bayonet mounts

Cost Comparison: DIY vs Professional

Need Professional Help?

• Washing machine repair service
• Bosch appliance repair

FAQ

Q: How do I distinguish pump failure from a simple blockage? A: Clean the filter, confirm impeller spins freely, start a drain cycle. Listen: humming = motor works (blockage downstream). Silence = dead motor (replace). Grinding = debris inside pump housing.

Q: Is BSH 00145787 compatible with all Bosch washers? A: Fits most WAT, WAS, WAW series from 2008-2022. Compact models and some newer WGA series may use a different pump. Always verify by model number.

Q: How long should a drain pump last? A: 8-12 years with proper maintenance. Foreign objects (coins, pins, underwire) damage the impeller and shorten life. Regular filter cleaning every 3 months is the best prevention.

Q: Can I replace just the impeller? A: No — on Bosch drain pumps, the impeller is molded directly onto the motor shaft. It is not a separate serviceable part. Replace the entire pump assembly.

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